To improve the performance of various types of machinery, for example tractors, they can be provided with front wheel drive. While the front wheels and tires are typically smaller than the rear, by driving both the front and rear wheels, tractive efficiency is improved. A mechanical front wheel drive requires a front drive axle with more components compared to a front axle without mechanical front wheel drive. Efforts to further improve tractive efficiency have also included axles with dual wheels on each side as well as axles with tracks on each side.
Many different steerable knuckle designs have been used on machinery with wheel drives and track drives. For wheel drives, the spindle on the knuckle supports the weight of the vehicle through the wheel and allows rotation of the wheel. Going from wheel drive to track drive on a steerable axle can be a challenge. With tracks, the drive wheel is separate from the track undercarriage. The track undercarriage supports the weight of the vehicle, and the drive wheel propels the track and the vehicle. The challenge can be getting the structural support from the undercarriage of the vehicle through the steerable knuckle. One solution has been to use an external bearing support that connects the drive wheel to the undercarriage and to support the weight of the vehicle through the external bearing support. However, that solution requires an extra bearing support and extra hardware to mate the external bearing support to the axle of the vehicle and may require external oscillation stops to prevent the track undercarriage from pivoting too far forward or backward while traveling over rough terrain.
It may be desirable to have a steerable knuckle that is a one-piece integrated knuckle solution, and/or that includes a spindle for power transmission to a drive wheel of a track drive, and/or that has structural support to the undercarriage of the vehicle.